The present invention is an improvement over cable extension potentiometers and other types of linear position transducers that translate linear movement into rotary movement by means of a string and drum. Important considerations in the design of these types of linear position transducers include accurate linear response, increased sensitivity to small linear movements, precise output over a period of repeated use, durable construction in order for the transducer to withstand acceleration and shock, transducer flexibility in handling lateral movements, and simplicity of design for ease of manufacture and replacement of worn parts.
The linear position transducer of the present invention attempts to maximize the foregoing considerations in a transducer that is relatively small in size and light in weight.
The following patents are provided for background purposes: U.S. Pat. No. 5,236,144 of Kautz, titled "Cable Extension Linear Position Transducer," issued Aug. 17, 1993; U.S. Pat. No. 5,021,648 of Jones, titled "Motion Tranducing through Conversion of Linear Motion to Circular Motion," issued Jun. 4, 1991; U.S. Pat. No. 4,181,959 of Tateishi, entitled "Stored Information Transferable Means for a Combined Electronic Digital Scale and Calculator," issued Jan. 1, 1980; U.S. Pat. No. 4,181,960 of Tateishi et al, entitled "Tape Reel and Detector Assembly for an Electronic Combined Digital Scale and Calculator," issued Jan. 1, 1980; U.S. Pat. No. 5,317,931 of Kalami, entitled "Apparatus for Sensing Deflection in a Crash Test Dummy Thorax," issued Jun. 7, 1994; U.S. Pat. No. 5,035,064 of Care, entitled "Linear Measuring Device," issued Jul. 30, 1991; U.S. Pat. No. 4,130,940 of Densmore, entitled "Boom Length Sensing and Indicating System with Self-Synchronization," issued Dec. 26, 1978; U.S. Pat. No. 4,037,326 of Booth et al, entitled "Trolling Apparatus," issued Jul. 26, 1977; U.S. Pat. No. 3,780,440 of Taylor, entitled "Measuring Instrument," issued Dec. 25, 1973.